[tes-i-too
r-uh; It. tes-see-too-rah] 
[-toor-ey; It. -too-re] . | the general pitch level or average range of a vocal or instrumental part in a musical composition: an uncomfortably high tessitura. |
| tes·si·tu·ra (těs'ĭ-tŏŏr'ə) n. The prevailing range of a vocal or instrumental part, within which most of the tones lie. [Italian, from Latin textūra, web, structure; see texture.] |
tessitura
(Italian: "texture"), in music, the general range of pitches found in a melody or vocal part. It differs from the compass of a piece to the extent that it does not take into account the extremes of the piece's range but is concerned with the way in which the vocal line is arranged or situated. The tessitura of a piece, therefore, is not determined by a few isolated notes of extraordinarily high or low pitch but rather by which part of the range is most consistently used; for example, the role of Siegfried in Wagner's Ring operas extends from c to c", but its tessitura would be considered extremely high (and consequently very demanding) because the tenor is frequently required to sing long phrases in the range c' to a'. Added to the strain of singing in such a high tessitura is the full volume and dramatic intensity often required for such parts
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